Nonshrinkable wood panel



Feb. 15; 1938.

A. ELMENDORF 2,108,479

NONSHRINKABLE WOOD PANEL Filed March :11, 1935 2 Sheets-Shee t l 5, :1938. A. ELMENDORF N ONSHRINKABLE WOOD PRNEL Filed March ll, 1935 2 Sheets-Sheet 2 Patented Feb. 15, 1938 I 2,108,479

arcane I woon PANEL Aunt Elmcndorf, Chicagmlill.

Application rch 11, 1935, Serial No. 10,451

a (Ci. ea-er) The manufacture of large thick panels of crushing strength and also great tensile strength wood faced with veneer, where change in sizeor in the direction of its thickness and will not inshape under different atmospheric conditions is crease or decrease in thickness when its moisof vital importance, has long presented problems ture content increases or decreases. What I bevery dimcult of solution. What is perhaps the lieve to be the best form of filler is a cellular best panel of this type, previously made, is that structure composed of two sets'of strips of woods in which a solid slab-like core is first built up crossing and interlocked with each other, in a of narrow boards placed on edge, side by side, manner common in so-called cell cases. The and glued together; facing sheets of veneer begrain of all of the wood in each strip may run ing, then glued to such core. Such a panel is, crosswise of the strip so as to extend from top however, very expensive and also very heavy. to bottom in the walls of the cells and thus be The object of the present invention is to pronormal to the planes of the facing members. duce a thick panel of wood or wood and other Such strips are rather fragile and may break fibrous material which.shall be light, strong and during the handling thereof. Strips of plywood s comparatively inexpensive, and which shall re-- are preferablefor some purposes since they do tain its initial size, shape and surface configuranot possess the weakness inherent in strips in tion under widely varying conditions with respect which all of the grain is transverse. In some to temperature and moisture content. instances, however, there may be only one set In carrying out my invention, I employ paralof strips. Where all of the strips are parallel to lo! facing members glued to opposite sides of a each other the spaces between them may be filled slab-like core or filler full of openings or spaces; with strips of corrugated paper board standing 20 the construction being preferably cellular, comon edge, or other suitable material, if desired. prising numerous similar cells placed side by side Ordinarily, where a panel is manufactured in 7 across the length and width of the core or filler. a size which it is to retain permanently as, for

The filler, being full of openings, is light and, example, a panel which is to constitute a door 25 as it contains much less material than would a or a table top, the filler will be surrounded by a solid member of the same dimensions, it is comframe of the same thickness as the filler. In paratively inexpensive. The crushing strength such case the facing members are glued simultaof the filler, effective to resist pressures on and neously to the filler and to the frame. By maknormal to the plywood facing members must be ing the frame members of plywood in which the 30 comparatively great, not only to give strength plies are disposed at right angles to the plane to the panel but to permit the gluing of the plyof the frame, so that the grain in one or more wood members to the filler under high pressures. of the plies in each member is also normal to Also, the areas of contact between the filler and such plane, the frame is non-expanding and noneach facing member must be so spaced as to contracting in the direction of its thickness,

hold the spans of facing material between adjanamely, in a direction normal to the facing memcent areas of support against such distortion as bers.' Also, since the grain in some of the piles might otherwise occur. The facing members of the frame members extends longitudinally of must be of types which expand and contract such members, the frame does not change in 40 across their lengths and widths, under changes length or width under variations in its moisture 40 in their moisture content, to a much lesser extent content. than the expansion or contraction across the In all forms of my invention, assuming the grain of a piece of wood under similar condigrain in at least one ply of each plywood facing tions. The filler, on the other hand, must not member to run crosswise of the panel and in expand or contract materially in thickness on another ply to run lengthwise of the panel, 45

account of changes in the moisture content there is wood grain extending lengthwise, crossthereof. wise and through the thickness of the panel; and Plywood is preferably employed for the facing therefore the panel cannot increase or decrease members, although various types of boards of in length, width or thickness on account of .,0 fibrous materials, particularly where the fibrous change in its moisture content. materials are compacted, will serve fairly well. The various features of novelty whereby my The filler, or at least the elements thereof that invention is characterized will hereinafter be perform structural functions, is wood some of pointed out with particularityin the claims; but, the grain in which is normal to the facings, or for a full understanding of my invention and approximately so. Such a filler possesses great of its pbjects and advantages, reference may be 55 2 had to the following detailed description taken in connection with the accompanying drawings, wherein:

Figure 1 is an elevation of a panel embodying the present invention, the front facing member being broken away at two of the corners; Fig. 2 is an edge view of the panel shown in Fig. 1; Fig. 3 is a perspective view of one corner of the panel, on a much larger scale, partly broken away to disclose the interior construction; Fig. 4 is a perspective view of a fragment of one of the filler strips; Fig. 5, is a plan view of a comer of a modified form of panel, the upper facing member being partly broken away; Fig. 6 is an edge view, partly in section, of the fragment of panel appearing in Fig. 5;-Fig. 'l is a view similar to Fig.6showing another modification; Figs.8and 9 are views similar to Figs; 5 and 6 illustrating a still further modification; Fig. 10 is a plan view of still another form of panel, parts of the upper facing member being broken away; Fig. 11 is an edge view of the panel appearing in Fig. 10; and Fig. 12 is a view similar to Figs. 6 and 7, illustrating further modifications.

Referring to Figs. 1 and 2 of the drawings, i represents a wooden panel of any desired length, width and thickness. In the arrangement shown, it comprises two facing members 2 and 3 extending across opposite sides of and glued to a rectangular frame 4. The hollow interior of the casing or housing produced by the members 2, 3 and 4 contains a cellular flller or core 5, which is also glued to the facing members. The details of these several elements are more fully shown in the larger scale views, Figs. 3 and 4. Referring to these latter figures, it will be seen that the facing members are of plywood, each containing two plies in one of which the grain of the wood runs across the width of the panel and in the other of which the grainextends lengthwise of the panel. Each side and end member of the frame 4 is also formed of plywood, the several layers or plies being arranged aisrlght angles to the planes of the facing members 2 and 3. Also, in the frame, the grains in some of the piles are disposed at right angles to the planes of the facing members, while the grains in other plies extend longitudinally of the respective frame members of which such plies form part. The frame members preferably meet in miter joints, as shown. The filler 5 illustrated is composed of thin strips of wood, notched as indicated at 6 in Fig. 4, arranged in two groups crossing each other at right angles and interlocked at their notches. The important consideration is that the grain of the wood in these strips runs across the width of the strips, namely, from one broad face of the filler to the other. Consequently, the grain of the wood in the filler is normal to the planes of the facing members. The members of a the frame 4, since they all contain grain that is normal to the facing members, may be regarded as being simply thick filler elements. It therefore follows that the strips constituting the filler proper may be plywood members as long as some of the wood grain in each strip is normal to the facing members. Furthermore, instead of mak ing the frame of plywood, it may in some cases be made of wood whose grain is at right angles to the facing members.

The strips constituting the core or filler may be of any desired thickness and be spaced any desired distance apart. .Since the gluing of the facing members to the frame and to the filler can best be done under heavy pressure, the total area of wood in the filler in a plane parallel to the broad faces thereof should be suflicient, at least, to avoid crushing of the wood in the filler under the load thus imposed. Also, where it is desired to apply finishing veneers after the panel as a whole has been completed, it may be necessary to employ even greater pressures for that purpose than for the gluing of the body of the panel. The strips may be made sturdy enough to permit this. It should be noted that in any event the strips should be so stiff as not to bend under the compressive forces that are imposed upon the same in the process of manufacture of the panel. The spacing of the strips may vary considerably. For example, I have obtained good results with a one-half inch spacing and also with a spacing of one inch. The spacing of the strips and the stiffness of the facing members are more or less related. If the facing members are comparatively flexible a lesser distance between strips is necessary than in the case of more rigid facing members.

It will be seen that the panel as a whole has wood grain running across the entire length and width thereof, in both the frame and the plywood facings, and other grain extending from one facing member to the other, normal to the latter, in the filler and in the frame. Thus each of the three dimensions of the panel is determined and fixed by wood whose grain runs parallel thereto, and these dimensions are therefore not subject to change by reason of variations in the moisture content of the wood. Consequently, a panel that is flat initially will remain so, as it cannot warp or be otherwise distorted. The filler, although giving great strength and rigidity to the panel, is light, contains but little wood, and is readily assembled; so that the panel as a whole is light and comparatively inexpensive.

In Fig. 3 one of the plies of each facing member is shown as being quite thick so that these members are rather stiff. In Figs. 5 and 6, on the other hand, both plies of each of the twoply facing members, 1 and 8, are thin. Therefore the strips in the filler 9 are spaced only about one-half as far apart as in Fig. 3. Figs. 5 and 6 also show a finishing layer iii of thin veneer covering the outer edge faces of the frame 4. The veneer I0 is carried up past the edges of the facing member I and 9 and so must be applied after the panel has been otherwise completed.

In Fig. '1 the construction is the same as in Figs. 5 and 6 except that the facing members II and ii are three-ply instead of two-ply.

In Figs. 8 and 9 there is shown a panel whose core or filler l3 contains only a single set of strips paralleling each other; the filler being surrounded by a frame I4 and lying between facing members i5 and I6. One ply of each facing member, the inner ply or cross band in the illustration, is made thicker than the other and the grain thereof extends crosswise of the strips l3, insuring stiffness and rigidity. The spaces between the strips are shown as filled with strips I! of corrugated board standing on edge.

In Figs. 10 and 11 the panel is composed simply of facing members and an interposed filler. The facing members, indicated at l5 and iii, are like those in Figs. 8 and 9, whereas the filler, indicated at 9, is like the corresponding element in Figs. 5 and 6. a

All of the spacing strips may be pieces of plywood as are the strips 20 in Fig. 12. The strips 20, which may be said to be representative of the aioaewa strips in any of the fillers that have previously been described, are shown as being three-ply, the

grain in the two outer plies being normal to the face members 2i and 22. The face members 2! and 22 are of fibrous material, preferably compacted; the fibers being so disposed that there is much less shrinkage or expansion in any direction in the planes of the said members, due to,

changes in moisture conditions, than would occur across the grain of a wood member of the same size and shape, under the same conditions.

While I have illustrated and described with particularity only a single preferred form of my invention, with a few modifications, I do not desire to be limited to the exact structural details thus illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constitut ing the appended claims.

I claim: v

1. A panel comprising a rectangular frame of wood, plywood facings extending across opposite sides of and secured to the frame, each facing containing plies in which the grains are respectively at right angles to the axes of the frame, at least some of the grain in each member of the frame running through the same from one of said facings to the other and approximately normal to the facings, and a filler in the space enclosed by the frame and the facings, the filler including pieces of wood distributed across the length and width of the filler whose edge faces are glued to the said facings and contain end grain.

2. A panel comprising a rectangular frame of wood, plywood facings extending across opposite sides of and secured tothe frame, each facing 5 containing plies in which the grains are respectively at right angles to the axes of the frame, at least some of the grain in each member of the frame running through the same from one of said facings-to the other and approximately norsaid strips being arranged in two groups in each of which the strips are parallel and are disposed at right angles to those of the other group.

3. A panel comprising a rectangular frame of wood, plywood facings extending across opposite sides of and adhered to the frame and a filler including strips of wood arranged on edge and fitting between said facings, each member of the frame containing a layer of wood whose grain extends throughout the thickness thereof and is normal to the facings and other wood whose grain extends from one end of such member to the other, each facing containing a layer of wood whose grain extends across thewidth of the panel and another layer whose grain extends across the length of the panel, and the grain in at least some of said strips being normal to said facings.

ARMIN ELMENDORF. 

